Poly (sodium 4-styrene sulfonate)-modified hydroxyapatite nanoparticles in zein-based scaffold as a drug carrier for vancomycin.

In order to prepare bone tissue engineered scaffolds, zein, a natural polymer isolated from corn, was used as a starting material. Zein provides ideal properties for tissue engineered scaffolds, and the products derived from its degradation are non-toxic. To enhance the osteogenic properties of the scaffold, hydroxyapatite mineral was used in the form of nanospheres. Hydroxyapatite nanoparticles are designed to carry a drug in addition to the role they play in bone tissue engineering. The surface of the hydroxyapatite nanoparticles was modified with negatively charged poly (sodium 4-styrene sulfonate) polymer, and their surface was then loaded with positively charged Vancomycin as a model drug. The scaffolds were evaluated by structural and cellular assays. FTIR and particle zeta potential tests confirmed the presence of PSS and Vancomycin in nanoparticles. The results showed a decrease in the porosity of the scaffolds and a reduction of scaffold degradation over an eight week period by increasing the concentration of hydroxyapatite nanoparticles, compared to the pure zein sample. It was observed that increasing the concentration of nanoparticles to an optimum concentration can improve the mechanical properties of scaffolds. The drug release from the scaffolds over two weeks was increased with an increase in hydroxyapatite concentration, and cell viability assays showed >90% viability of cells in scaffolds containing hydroxyapatite nanoparticles, which were confirmed to be accumulating in a proper fashion according to cell adhesion assays.